This invention relates to apparatus for bending and more particularly for initially or pre-bending pairs of concrete curbing as they emerge from an automatic casting machine and while still in a zero slump state. Pre-cast concrete curbing of this type is conventionally formed with one vertical side and the other side slanted, that is, being wider at the base and upwardly slanted to a narrow top. Curbing emerges from the machine in pairs, with the slanted sides facing and slightly separated from each other so as to form a substantially V-shaped space therebetween.
Thereafter the curbing pairs may be pre-bent by forcing an elongated device or tool having a generally V-shaped cross-sectional configuration and bowed convex sides, i.e. sides curving from end to end, into the V-shape space so as to force the curbs to be bent away from each other in opposite curves. The amount of bend can be controlled by the depth of insertion of the such device, the deeper the insertion, the greater the bend. After such pre-bending step, a second and final step is performed with an elongated, generally inverted U-shaped bending tool which is formed with the required bending radius and of an internal configuration to fit the pre-bent curbing. A different tool is provided for each desired radius. This second tool is then sequentially forced over each of the pre-bent curbings so as to complete their final curvature. The thus formed curved curbings are then kiln set.
The equipment and operational manner above referred to is described in greater detail in applicants' prior patent, U.S. Pat. No. 3,941,545 issued Mar. 2, 1976. In that regard the above citation and discussion constitutes applicants's prior art statement and a copy of that patent is included in the filing of the subject application. While the equipment therein described is satisfactorily suited for the indicated purpose, it has been found that upon withdrawing the pre-bending tool, its frictional contact with the pre-bent sides of the curbing pairs can upset and distort the surface thereof which can result in damaged curbing. Accordingly it would be desirable to eliminate such potential for damaged curbing.